The present invention relates generally to the field of knee controls for machines, and, more particularly, to a knee control mechanism for attachment to industrial machines, such as sewing machines used in the garment and upholstery industries, during operation of which the machine operator is in the standing position.
Previously, control mechanisms for operation of sewing machines were limited in that they generally were structured for use in only the seated position and were generally not adaptable for use in the standing position. Also, many known machine controls were only useful for in home purposes and not well suited for adaption to industrial grade equipment.
Furthermore, most known foot and knee control devices cannot be adjusted for individual operator preferences or needs, due to body size differences, right or left hand operation, and the like. These limitations are particularly important in industrial situations where increased fatigue and errors result from by staying in one position too long, thereby decreasing efficiency of the entire manufacturing operation. Of course, operator fatigue also results in increased injuries, and general health problems which may add to employee time off work.
Also, with many known machine controls it is necessary for a standing operator to have his or her weight on only one leg during at least a substantial part of the time of operation, in order to foot-operate the machine with full control of the machine speed, direction of operation, and other various machine functions. Such limited operator positioning of course lends itself to muscle cramping, back injuries, muscle strains, etc., with the expected negative results in work performance.
In the present knee control mechanism the operator stands and is able to move the knees freely in two basic movements, forwardly and rearwardly (i.e., in and out) or to one side or the other of the operator. Typically, but not necessarily, with the new mechanism, movement of either or both of the knees forwardly, in, away from the operator, makes the machine go faster, and is usually progressive in nature. However, a more "on" and "off" nature of control can be attained, depending upon the particular combination of switching and power elements provided, as will be clear from the following description.
Known industrial machines, such as sewing machines, typically use either a clutch operated motor or an electronically controlled motor. Knee controls have existed for use with either one or the other, but in both cases limitations existed. These are avoided with the new mechanism when used with an electronically controlled electric motor. Certain of these known mechanisms were mounted by attachment directly to the underside of a stand or tabletop upon which the machine being driven, such as a sewing head, is supported.
Thus, in instances where the table top is vertically adjustable, the knee control mechanism attached therebeneath is necessarily simultaneously moved up and down to an equal extent with movement of the table top. This may be quite undesireable and limiting to the machine operator who may wish, for example, to have the work surface higher, but not have the height of the knee control pedals shifted. These known devices were simply not structured for attachment or operative support other than by connection to the table top.
Furthermore, known knee controls are generally not adjustable other than by vertically moving the work surface to which the control is connected. Generally, very little or no adjustment in any other direction is possible.
Another limitation with such previously known knee controls is that they occupy a great deal of longitudinal space beneath the work surface, which space is often at a premium, being needed for attachment or other placement of other, accessory equipment, particularly near the center of the table where the operator is often required to stand. The structure of known devices generally severely limits or makes impossible the connection of some other equipment, and often requires positioning of the speed controller and/or motor in an awkward or otherwise undesireable position.
By contrast, the new knee control mechanism is structured for connection to the stand or other support structure, off to either the right or left of the operator's usually standing position, and is not connected to the table top at all. So, the height of the work surface can be selectively adjusted completely independently from the height of the new knee control mechanism. Additionally, the speed controller can be positioned completely at the back of the machinery, out of the operator's way and out of the way of other equipment.
The new mechanism is structured so as not to occupy such a large amount of space beneath the work surface, and instead has a generally narrow construction which, except for the main knee push plate, usually extends transversely of the of the work surface and off to one side of the operator so as to be out of the way, as well as being rapidly adjustable in an extremely facile manner.
With the new knee control mechanism the in-and-out knee movement discussed may start from a neutral position or from a braked (completely stopped) or other machine condition. In such a case the forward knee movement first takes the machine out of whatever condition it is in (eg. stopped) and then causes it to progressively operate faster.
The second basic knee movement offered with the new control mechanism is side-to-side. Either the left knee is moved to the left or the right knee is moved to the operator's right, depending upon the structure selected. Typically these movements cause a function of a switching, on/off nature, rather than being gradual or progressive. In the example shown and described hereafter, there are three "off" or "on" functions. With movement, a lever connected to a knee contact surface activates a first function, then with continued movement in the same direction the lever activates a second function, and so on, to the third function. Of course, other functions could be operated in like manner if so desired.
The mechanism illustrated and described herein allows sideways knee movement control only to the operator's right. However, by similar and appropriate "mirror-image" construction, as will be made clear, the mechanism can have the facility to provide control just as well by knee movement initiated to the operator's left.
Accordingly, it is among the several advantages of the present invention to provide a knee control mechanism for a machine, especially an industrial sewing machine, which is operated by knee pressure while the standing operator has both feet firmly on the ground at all times during machine operation.
It is also among the advantages of the invention, having the features indicated, to provide a machine knee control mechanism which can be selectively adjustable in more than one direction for increased versatility, in order to accommodate the individual needs and preferences of the machine operator to facilitate maximum productivity. These adjustments are intended to be accomplished at least in part by structural features of the knee control mechanism per se, and may also be accomplished in part by structural adaptations of the mechanism which permit it to be mounted on a frame or some other assembly for selective directional adjustment in relation to the machine to be operated by the mechanism.
It is further among the advantages of the present invention, having the features indicated, that the new knee control mechanism be economical to manufacture and relatively simple to operate in a facile and safe manner by a machine operator having little or no additional training and which mechanism may be adapted for operation with either the left or right knee of the operator, as may be desired, and which permits a substantial amount of machine control with only two basic knee movements.
It is also among the advantages of the present invention to provide a knee control mechanism, having the above features, which can be incorporated into new equipment and which is also suitable of attachment to existing machines for more efficient use thereof; and further which, if desired, permits rapid removal of portions of the mechanism to facilitate access to other parts of the equipment to which it is attached, for example, for access to a foot control mechanism also associated with the machine to be controlled.
Thus, the present invention is, briefly, the combination of a machine and a knee control mechanism for operation thereof. The mechanism has at least one knee contact surface operatively connected to the machine in such manner as to permit operation of the machine while the operator is standing with both feet firmly placed on the floor at all times. The knee control mechanism is positioned forwardly of and substantially entirely to either one of the right and left sides of the operator.
The invention is further, briefly, a knee control mechanism for standing operation of a machine. The mechanism includes a plurality of knee contact surfaces operatively mounted in connection with the machine, a plurality of fluid cylinders selectively contacted by the plurality of knee contact surfaces, and a speed control device connected to at least one of the plurality of fluid cylinders and controlled by selective activation of at least one of the plurality of knee contact surfaces.
Other objects and advantages will be in part apparent and in part pointed out hereinbelow.